1. Field of the Invention
The present invention relates to collapsible beverage containers which prevent liquids from leaking from between container sections.
2. Description of Related Art
Collapsible drinking cups have been used for decades with varying success in keeping the beverage contained within the cup. The cup allows for convenient storage and travel due to its ability to fit in a small space when in the collapsed position. The size and shape may vary, but such cups generally rely on a pressure fit between the container sections for preventing liquids from leaking out. The success of the pressure fit depends on the tolerance in the manufacture process, the ability to resist unwanted deformation such as dents and scratches, and the ability to resist deformation from pressures occurring while holding the beverage cup.
The inability of the prior art collapsible beverage cups to contain liquids effectively and consistently limits their use. Clothing is often a concern when using a collapsible cup, especially when a person is wearing formal or business wears. Spillage of some beverages creates a stain which, at best, is tough or expensive to remove, and at worst, permanently staining. Also, a person would not ordinarily use a collapsible cup on a desk where paperwork may be ruined, or in an auto where leakage would be a nuisance. More importantly, one would not even consider collapsing the prior art cups while a portion of the beverage was still in the cup, since they did not provide a liquid-tight seal in the collapsed position because of inadequate seals between the cup sections and in the lid. All of these problems are exacerbated by the inability of the cup to maintain itself in the extended position in the event that a minimal amount of pressure on the cup may in itself collapse the container. Prior art collapsible cups have other deficiencies that limit their usefulness and reliability.